The invention relates to a method for optically capturing a fingerprint or an object, and an apparatus with at least one screen, the screen comprising an upper optical cover plate under which a plurality of display pixels are arranged as light sources for the image to be represented.
Such apparatuses are known as display apparatuses with screens of any desired configuration. For example, LED or preferably OLED screens in mobile devices, for example in what are known as smart phones or tablet computers, are used as high-resolution touch screens. The problem here is, for example, data security when using such mobile devices which, because of a compact construction, have no space for incorporating a fingerprint reader, for example.
Fingerprint recognition systems comprise generally capacitive or optical surface sensors for capturing characteristic features of a fingertip. The recorded signals are often compared by a recording device with fingerprint features of authorized persons that are stored in a memory. If the fingerprint recorded by the fingerprint sensor matches a stored fingerprint pattern in terms of significant features, the recording device outputs a corresponding signal to an evaluation and control device which, for example, unlocks a door lock. If, for example, an unauthorized person tries to gain access, this is detected when comparing the recorded fingerprint features of the unauthorized person to the stored fingerprint features, and a signal transmission to the evaluation and control device is either suppressed or a failed-attempt signal is transmitted.
Furthermore, DE 699 20 126 T2 illustrates a fingerprint reader with a light source, a photosensor device comprising a plurality of photosensors formed on the light source and a surface formed on the photosensors, and a see-through, light-conducting layer formed on the photosensor device. The arrangement of such a fingerprint reader in particular in what are known as smart phones or tablet computers is a problem, since here little space is available as installation space in a housing, but relatively high data security and thus effective access control is desired.
Moreover, a surface-capacitive touch screen is known which substantially a film coated with a see-through metal oxide, which is laminated onto a transparent carrier plate, usually glass. An alternating voltage is applied to the corners of the coating so as to generate an electric field. In the event of contact by touch, a small charge transport is produced which is measured in the discharge cycle in the form of a current at the corners. The resulting currents from the corners are in direct relationship with the touch position.